Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model

Gatzsche, Kathrin; Babel, Wolfgang; Falge, Eva; Pyles, Rex David; Paw U, Kyaw Tha; Raabe, Armin; Foken, Thomas

doi:https://doi.org/10.5194/bg-15-2945-2018

Articles | Volume 15, issue 9

https://doi.org/10.5194/bg-15-2945-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-15-2945-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 15, issue 9

Research article

|

16 May 2018

Research article |

| 16 May 2018

Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model

Kathrin Gatzsche, Wolfgang Babel, Eva Falge, Rex David Pyles, Kyaw Tha Paw U, Armin Raabe, and Thomas Foken

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Final revised paper (published on 16 May 2018)
Preprint (discussion started on 02 Nov 2017)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'review of "Application of the ACASA model for a spruce forest and a nearby patchy clearing"', Anonymous Referee #1, 04 Jan 2018
- AC3: 'Response to the referee #1', Kathrin Gatzsche, 28 Feb 2018
RC2: 'comments to the manuscript "Application of the ACASA model for a spruce forest and a nearby patchy clearing" by K. Gatzsche et al.', Anonymous Referee #2, 05 Jan 2018
- AC4: 'Response to the referee #2', Kathrin Gatzsche, 28 Feb 2018
EC1: 'make use of the interactive discussion', Andreas Ibrom, 06 Jan 2018
- AC1: 'Response to the editor', Kathrin Gatzsche, 24 Jan 2018
  - RC4: 'Response to the comments from 25 Jan 2018', Anonymous Referee #2, 25 Jan 2018
    - AC2: 'Response to the referee #2', Kathrin Gatzsche, 25 Jan 2018
RC3: 'Review of the MS ” Application of the ACASA model for a spruce forest and a nearby patchy clearing” by Kathrin Gatzsche et al.', Anonymous Referee #3, 08 Jan 2018
- AC5: 'Response to the referee #3', Kathrin Gatzsche, 28 Feb 2018
EC2: 'prolonged interactive discussion', Andreas Ibrom, 25 Jan 2018
- AC6: 'Response to the editor, edited manuscript', Kathrin Gatzsche, 28 Feb 2018

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (28 Feb 2018) by Andreas Ibrom

ED: Reconsider after major revisions (21 Mar 2018) by Andreas Ibrom

AR by Kathrin Gatzsche on behalf of the Authors (23 Mar 2018) Author's response Manuscript

ED: Publish as is (23 Mar 2018) by Andreas Ibrom

ED: Referee Nomination & Report Request started (26 Mar 2018) by Andreas Ibrom

RR by Anonymous Referee #1 (26 Mar 2018)

Suggestions for revision or reasons for rejection

General comments:

The quality of the paper has been improved.

I’m still moderately enthusiastic about the originality level of the paper but at least specific advances compared to previous publications on the same site/model are more clearly presented. To this purpose, reorganization of the introduction section helps, even if I still have some remarks on it (see specific comments).

I still find the title very broad. It gives no idea of the precise scientific question you want to answer.

I agree with the authors’ proposition of keeping the section 3.2.4. (“tile approach for a mixed forest site”) now that the background is better explained, with the possibly biased use of remote sensing products (MODIS) vs flux dataset.

Even if most of my previous comments/suggestions have been taken into account, there are still some of them that where not really processed and when reading your new manuscript, they arose again in my mind so I simply reproduced them in the specific comments section after having adapted the line numbering for clarity sake.

Specific comments:

P1L13-P2L12: I’m again confused by your writing style. This is an important part of the paper and I think that the argumentation you gave in your first response to the editor (the part starting with “Reviewer #2 and #3 proposes the use of a 3D model rather than …” in your point4 was much clearer than what you have written here. I will therefore avoid detailed comments on this part and suggest revisiting it.

P2L24-29: “However, the influence of secondary structures on the energy balance cannot be taken into account by a one-dimensional model. The ACASA model is much better suited to handling coherent structures and counter gradients than classical SVAT models with a first order closure”. This sounds like a repetition of what is written in the first part of the paragraph. Please merge the two. And the next sentence is not connected enough to/not explicit enough in the context of the § content.

P3L2: I would appreciate here a short comment on the dataset used, in order to help the reader understand why you need both datasets (and then understand better the current title).

P8L21: “The discrepancy between measured and simulated NEE can be an effect of the unclosed energy balance on the CO2 fluxes”. I understand what you mean but this is a complicated way of saying that if CO2 exchanges share the same transport processes than heat exchanges (scalar similarity), measured CO2 exchanges should be underestimated on the same level as heat fluxes. And this hypothesis being far from widely accepted, this point should be discussed further.

P9L1: “whereby a spectral method of the non-linear flux averaging of surface characteristics (friction, roughness length) according to Hasager and Jensen (1999) is employed (Göckede et al., 2006)”. I still do not understand this part of the sentence. Please be more explicit.

P9L14-18: This § should be reorganized to avoid repetitions.

P14L21-22: “For Bo > 1, the buoyancy correction overestimates the effect of thermal convection on the energy balance closure and the true correction might lie between both correction methods”. I do not understand this sentence. Why EBC-HB should overestimate H when H is dominant? Please be more explicit.

P17L8-9: “This could also be an overestimation by the measured fluxes due to the turbulence and the forest structure, discussed by Foken (2017b)”. Please explain what you mean, in order to have this manuscript self-standing. It’s a bit more explicit in the conclusion but should be moved here.

P18L2: “Because a large contribution of the unclosed energy balance is a missing sensible heat flux, we used the modeled data, wich close the energy balance by definition - as an etalon, for the validation of the correction methods”. I do not understand the link between the first part of the sentence and the second part. Whether is measured H or measured LE the main responsible for the non-closure of the energy balance, you can decide to use the modeled values as the reference. Please clarify.

P18L14-15: “Therefore, the Bowen-ratio correction is not a method that is applicable for the correction of the measurement errors that occur”. Confusing since the reader does not know if this assertion holds for a given range of Bo or for the whole range.

Technical comments:

P23L6-7: here you use 2017a for the whole Foken book while on L23 of the same page, you use it for a specific chapter. On the other hand, you use 2017b for another specific chapter on L26. Please standardize your choices.

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RR by Anonymous Referee #2 (11 Apr 2018)

ED: Publish subject to minor revisions (review by editor) (14 Apr 2018) by Andreas Ibrom

AR by Kathrin Gatzsche on behalf of the Authors (26 Apr 2018) Author's response Manuscript

ED: Publish subject to technical corrections (27 Apr 2018) by Andreas Ibrom

AR by Kathrin Gatzsche on behalf of the Authors (30 Apr 2018) Manuscript

Short summary

The ecosystem is a significant sink of carbon dioxide. To quantify this sink, very complex and validated models are required. However, the comparison of modeled and measured energy and matter fluxes in a heterogeneous landscape is still a challenge. On the one hand, models must be applied for various surface types, while on the other hand the comparison of the fluxes is only possible based on the flux source areas. This paper treats the potential aggregation of modeled fluxes and its validation.